A paper recently published in Global Environmental Change by Brysse et al. (2012) examined a number of past predictions made by climate scientists, and found that that they have tended to be too conservative in their projections of the impacts of climate change. The authors thus suggest that climate scientists are biased toward overly cautious estimates, erring on the side of less rather than more alarming predictions, which they call “erring on the side of least drama” (ESLD).

In this paper, Brysse et al. examined research evaluating past climate projections, and considered the pressures which might cause climate scientists to ESLD.

Conservative Climate Projections

While we have recently shown that the Intergovernmental Panel on Climate Change (IPCC) temperature projections have been exceptionally accurate, several other projections in the IPCC reports have been far too conservative.

Sea Level Rise

For example, Rahmstorf (2007) and more recently Rahmstorf et al. (2012) showed that sea level is rising at a rate inconsistent with all but the highest IPCC scenarios (Figure 1). Rahmstorf et al. (2012) concluded,

“The satellite-based linear trend 1993–2011 is 3.2 ± 0.5 mm yr-1, which is 60% faster than the best IPCC estimate of 2.0 mm yr-1 for the same interval.”

Figure 1: Sea level measured by satellite altimeter (red with linear trend line; AVISO datafrom (Centre National d’Etudes Spatiales) and reconstructed from tide gauges (orange, monthly data from Church and White (2011)). Tide gauge data were aligned to give the same mean during 1993–2010 as the altimeter data. The scenarios of the IPCC are again shown in blue (third assessment) and green (fourth assessment); the former have been published starting in the year 1990 and the latter from 2000.

The main reason these sea level rise projections have been too low and that the IPCC almost certainly underestimates future sea level rise is that their models do not include the effects of dynamic ice processes from chunks of ice breaking off into the ocean (“calving”), then melting. The IPCC approach in attempting to account for these processes considers recent contributions to sea level rise from ice sheet melt, then “assume that this contribution will persist unchanged.” This is certainly a conservative approach, and the primary reason their sea level projections have been low.

Arctic Sea Ice Decline

Three years after the IPCC Fourth Assessment Report was drafted, the 2009 Copenhagen Diagnosis examined the latest climate research to effectively update the IPCC report. In addition to confirming the Rahmstorf finding that the IPCC has underestimated sea level rise, the Copenhagen Diagnosis also found that the IPCC has dramatically understimated the decline in Arctic sea ice extent (Figure 2).

“The IPCC projections are based on estimates that CO2 emissions in China increased at an annual rate of about 3 to 4 percent during the past 10 years (IPCC, 2007a; IEA, 2007), but a subsequent province-based inventory concluded that emissions actually increased at a higher rate of about 10 to 11 percent (Auffhammer and Carson, 2008)….Emissions from a number of other developed countries were also higher than agreed-to targets.”

Permafrost Melt and Carbon Feedback

The Copenhagen Diagnosis notes that the global warming amplification (feedback) from carbon released as a result of permafrost melting has not been accounted for in any of the IPCC projections. A recent UN Environment Programme report warned that failing to account for this feedback will result in an underestimate of future warming.

Other Climate Impacts

The NRC report notes that according to Déry and Brown (2007), northern hemisphere snow cover may also be declining at a faster-than-expected rate, and the Copenhagen Diagnosis states that rainfall has become more intense in already rainy areas, and “recent changes have occurred faster than predicted“.

So while the IPCC and the climate science community in general has under-predicted quite a few climate impacts, there are very few examples where they have over-predicted these changes.

“Erring on the Side of Least Drama” (ESLD) to Avoid Alarmism

The IPCC and climate scientists are often accused of “alarmism”, but clearly Brysse et al. demonstrates that these accusations are wholly unfounded and misplaced.

“Our analysis of the available studies suggests that if a bias is operative in the work of climate scientists, it is in the direction of under-predicting, rather than over-predicting, the rate and extent of anthropogenic climate change.”

In fact, Brysse et al. suggest that these frequent accusations of “alarmism” and other climate contrarian attacks on climate scientists may be one reason why climate scientists have under-predicted climate change, or erred on the side of least drama.

“The frequent attacks on Stephen Schneider—as well as attacks on other climate scientists such as Benjamin Santer and Michael Mann—suggests that one possible reason why scientists may have underestimated the threat of anthropogenic warming is the fear that if they don’t, they will be accused by contrarians (as was Schneider) of being alarmist fear-mongers. That is to say, pressure from skeptics and contrarians and the risk of being accused of alarmism may have caused scientists to understate their results.”

However, Brysse et al. note that from a scientific and statistical standpoint, under-predicting an effect by 10% is no less wrong than over-predicting an effect by 10%. Therefore, ESLD can introduce a systematic bias that leads to a reduction in the accuracy of climate projections.

The Ozone Example

Between 2008 and 2011, Brysse et al. conducted a series of interviews with numerous scientists studying and assessing ozone depletion. In February of 1992, NASA scientists studying the Arctic atmosphere issued a press release warning that a major Arctic ozone hole, like the one over Antarctica, could develop that spring. While the science behind the prediction was correct, unexpected factors intervened, and Arctic ozone depletion in 1992 was not as severe as the scientists anticipated.

“In the aftermath of the unrealized 1992 Arctic ozone hole prediction, NASA scientists were severely criticized in the conservative press for crying wolf, causing unnecessary panic, and acting according to emotional imperatives or an environmental agenda instead of according to the dictates of scientific objectivity.”

Subsequent to the barrage of criticism over this event, NASA has become more cautious in issuing press releases. Many scientists who researched ozone depletion have now become involved in the IPCC reports. In an interview in 2009, ozone researcher Jonathan Shanklin suggested that scientific assessments operate according to the “crying wolf principle: if you cry wolf too often, then nobody believes you anymore, and the sky does fall in“, and also suggested that in the case of recent IPCC predictions of future climate change, scientists’ “best guess for many of these [scenarios] were actually worse than those in the report.”

In other words, Shanklin suggests that the IPCC under-predicts climate impacts in order to avoid losing credibility due to …accusations of “alarmism”. Other scientists interviewed by Brysse who were involved in ozone research and the IPCC reports shared similar opinions.

Other Causes of ESLD

In addition to fear of being labeled as “alarmist” Brysse et al. discusses other possible causes of ESLD. For example, scientists tend to invoke the “principle of least astonishment”, whereby they typically choose the simplest of two possible hypotheses. However, the rate that climate impacts like Arctic sea loss and sea level rise are occurring and will occur is rather astonishing. Similarly, scientific conservatism introduces “an inherent bias in favor of existing knowledge and presumptions, and the avoidance of conclusions that seem excessively dramatic.”

Brysse et al. also believe “that the basic, core values of scientific rationality contribute to an unintended bias against dramatic outcomes…scientists are skeptical of all new claims, and ceteris paribus, the more dramatic the claim, the more skeptical they are likely to be.” Dramatic claims open scientists to criticisms not just from climate contrarians, but to their own peers as well.

The Dangers of ESLD

To sum up, climate scientists have tended to systematically under-predict many impacts resulting from climate change. Brysse et al. suggest they do so in “erring on the side of least drama” (ESLD)

in order to avoid accusations of “alarmism” from climate contrarians;

because scientists are skeptical by nature whereas climate impacts are dramatic;

and because dramatic claims open scientists to criticism from their peers.

However, the conservative bias imposed by ESLD produces a dangerous result.

“If climate scientists and assessors are erring on the side of least drama in their predictions, then they are not preparing policymakers and the public for the worst, because they are underpredicting what the worst outcomes might be.”

We will give the final word to Brysse et al.

“Our hypothesis of ESLD is not meant as a criticism of scientists. The culture of science has in most respects served humanity very well. Rather, ESLD provides a context for interpreting scientists’ assessments of risk-laden situations, a challenge faced by the public and policy-makers. In attempting to avoid drama, the scientific community may be biasing its own work—a bias that needs to be appreciated because it could prevent the full recognition, articulation, and acknowledgment of dramatic natural phenomena that may, in fact, be occurring. After all, some phenomena in nature are dramatic. If the drama arises primarily from social, political, or economic impacts, then it is crucial that the associated risk be understood fully, and not discounted.”

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Certainly couldn’t be that they receive all their research funding from Federal governments, and these governments want to underplay the seriousness so that they will not have to take any action. Nah, too simple, must be far more complicated.

Super and ME what is going on with you two? And, that means, Super you have to dig a bit more into having an argument with yourself.

We get your point. But, we want to move on from it. Yes, we’re toast but we don’t have to go down admitting we were not smart enough to sort this all out.

US and China are the poison pills of a healthy global environment. We know that for a fact.

So, can their be a more vital action President Obama can take than to travel to Beijing, sit with President XI and say we are in this together. Then he suggests our two governments bring together the knowledge base and tell them to report the details of a US China partnership to arrest climate change and all that will include…from mitigation to adaptation.

To see it, as partners, to the end. Many tomorrows before we see 2 degrees.

I sit on quite a few grant review panels and also act as a ad hoc reviewer for individual NSF grants. Politics is never an issue. Scientists are interested in exciting and credible research plans. Scientists are often cautious and understated in describing their results. However, this would not necessarily lead to underestimates in estimates. If politics were an important issue, we would see big changes in what research is funded when administrations change. We have not seen this with the exception of rules about stem cell funding under GW Bush.

ME and others “defending the scientists” from “defamation” – I can’t speak for the intentions or thoughts super had but I can speak about the content of their words – and the content of simply saying that governments influence the process is Not necessarily defaming the scientists. I’m suprrised to have to remind folks, but the governments influence what the IPCC works on, and that (as I’m almost certain was reported on this blog) included the political decision to not have IPCC include certain feedbacks that were “not understood well enough” but which the governments knew, that this lack of inclusion would make the predictions sound softer. So the ipcc scientists hands were tied, this is not defaming them (one could at most say that they should have protested more loudly) But this has been reported. It’s like the insanity of saying to doctors that the report they give to the patience should not make any statements at all about the effects of the second illness, a cancer, on longevity, because this second illness is “not well understood enough” That would be laughable. You’d give longevity estimates based on the better understood first illness *and* your medical report would also include statement, which while cautioning that the second disease (or second factor, if you like) is not as well understood, but it would take off as much as N years off life, with at least p% probability, etc…this was not allowed for IPCC to do – and not even *mentioning* (with even disclaimer-added predictions) any analysis based on certain feedbacks is bad science – but was as I recall forced upon the IPCC. The “I” in “IPCC” has “governmental” in it…and those influence what the scientists are allowed to, or tasked, to do…We focus on how Saudi Arabia or USA or China governments press to change the language, change a word here or phrase there…and that’s important too…but excluding key feedbacks from even inclusion in the analysis of what we can expect, that’s a huge blow to accuracy…and was not without political bias in effect and (one has to assume) intent – but the parties being criticized are not scientists but governments who set the framework within which the former operate….

Bingo! Right on target. Research findings have an associated degree of uncertainty. A conservative researcher will report those findings with the least uncertaintly, and in the process subject himself to the least criticism. A more adventurous researcher will report more expanded findings, along with the higher uncertaintly, and run the risk of higher criticism. If a researcher wants continued funding, and recognizes the sponsor wants the results with the least uncertainty, he will be motivated to report along those lines. One can characterize this behavior however they want, but if it has contributed to delay for taking action toward climate change, it is not a good situation.

Super, I am going to make a crazy guess that you have not downloaded IPCC 2007 AR4 WG1 and carefully studied the concept of “certainty” as used throughout that report, nor the supplemental document also on their website that attempts to explain how “certainy” was determined.

Did you know that the min and max on the range of temp projections is only stated with 66% certainty, or that they quantified a greater amount of uncertainty for the max values, rather than the lower ones? If you didn’t already know that perhaps you should be slow to crow about IPCC?

To borrow the 2nd illness example, cancer was a bad choice for the 2nd illness because we understand that one fairly well. Rather it should have been a mystery disease with eyeballs melting and nails falling out. The doc says “We can’t say much about it this other thing because we still don’t know why for sure or how fast those things will progress. So we’ll tackle the stuff we do understand and continue doing tests to figure out this other stuff in the meantime.”

Here the analogy really breaks down because the doc tells the patient exactly what to do so that illness #1 (the understood part) does not kill the patient in the meantime.

” we don’t have to go down admitting we were not smart enough to sort this all out.”
Oh, we’re smart enough alright. But, more than smartness is required; willpower most of all. Like all the stars, Elvis, Michael, Marilyn, they knew that drugs were bad and life-threatening, but their addiction over-rode their intelligence. Our addiction to the lifestyle that requires intensive energy use enabled by the unlimited availability of cheap fossil fuels will over-ride any meeting between USA and China politicians. Converting an addiction problem to a political problem insures the fundamental problem will never be solved.

I’ll be more specific. I’ve spent more than five decades in S&T, both as a performer and as a peer reviewer/member of evaluation boards/panels. Based on my experience, and studies on the topic I’ve read reported in the literature, the most important factor in the research reported is the funding source, and the second is the full picture provided by comprehensive analysis of the data. Probably, in most cases, especially when there are few commercially and politically sensitive issues involved, there’s no conflict between these two factors, and the research reported accurately reflects what the performers could have reported. But, in some cases, when push comes to shove, the funding source interests will predominate, especially if the performer wants continued funding.

A classic example of an industry-supported performer who chose to tell the truth and accept the consequences was Dr. George Louis Carlo. He was trusted by the Mobile Phone Industry in the US to be most competent to correctly assess the safety of the mobile phones, and was sponsored by that industry with 28 million dollars to make a very thorough examination of the safety. But after a few years of denying the hazards to the satisfaction of his sponsors, he changed his opinion in the face of accumulating evidence about the dangers and wrote a book about it. He stated, in part:
“…with medical science indicating increased risks of tumors, cancer, genetic damage and other health problems from the use of cellphones, the government and the cellphone industry have abandoned the public.”

Since the public communication of his findings, Dr Carlo “has been threatened, physically attacked, defamed, and his house mysteriously burned down.” Instead of listening to the well founded evaluation of the scientist the mobile phone industry trusted as most suitable for assessing the issue, they did not only ignore his results, but they sought to discredit him personally among reporters and other scientists.

C’mon, you’ve seen a number of cases of research fraud reported both in the literature and the popular press. This is the most extreme example. Next on the list is the type if research bias reported in the book Merchants of Doubt, where researchers unabashedly torque their findings to conform to their sponsors’ wishes.

But, there is a more insidious form, where researchers do limited experiments and perform limited analyses over limited regions of parameter space. What they report is a reflection of the data, and can be viewed as honest scientific output, but does not tell the full story that could be told from all the data or a full analysis of the data. That gets into the issue of ‘intent’, perhaps the central issue in any type of intelligence work, and is extremely difficult to evaluate.

Bottom line – I would not discount the motivations of researchers to please their sponsors in how they report their results.

I have to disagree with on that one superman1, the scientists who’d go along with something like that are few and far between….you only have to go back to the Bush administration to see many standing up for the truth in the face of (often implied career threats) severe pressure to toe the former Administration’s line on what they wanted for climate change…it consistently blew up in the administration’s face…thankfully. While the politicians don’t have our backs in this – the scientists (except for a very few) are doing their very best.

No, it is crime that does not pay. The extreme GOP never lacks for acceptable mortality rates thanks to the NRA, EssoKochs, pro-life, estate sale windfalls, free organ donors, and the federal government still owes them for freed slaves. Modelers of AGW can go through their whole lives without the shame/sadness of being correct. People in Iran were the first to die from my brand new earthquake predictions based on AGW. Ever since then, I calculated my numbers to be at least technically right and sufficiently large enough for an adequate warning.

The CO2 projections are worse. But the temp rise is less. So the temperature/CO2 rise is off. Sensitivity is lower than in the Scenarios?

The sea-level of 3.2 mm/yr: doesn’t that include 0.5 mm/yr of GIA, which is not the tidal guage, or what we see, but what would happen if the continents were’t rising. The IPCC didn’t include GIA in the projections. Still higher, but less so.

Reductionism is so accepted as the one and only way that it is not even questioned. This is sad, unfair and wrong because when we don’t understand the correct reason for a phenomenon, we blame the people involved. This is what is happening in this case where the scientists are only doing what is expected of them which is use reductionism rather than systems thinking and mathematics, ME

And, John, our brightest climate scientists now have to spend time with their Chinese counterparts to get to the same conclusions and then report them.

China happens to be a highly vulnerable nation to changing temperature and precipitation. It is becoming well known to Chinese leaders something is threatening to their civil composure and that is sacred in China. Just as Congress members are beginning to count up the billions spent and to be spent on weather disasters. Something is going to break soon and it is a higher level of reason among government leaders.

I invited lots of comments there but we know it to be self evident,at least for me, this cannot be solved by the generosity of American strangers.

Meteorologists have long ago gotten over the “drama avoidance” problem. Whenever a likely hurricane or tornado situation approaches they’re asking themselves, “what’s the 95th percentile worst thing that can happen?” It’s their job to save lives and property by accurately predicting the worst that can be expected. In the Netherlands, they try to fortify their dikes against a 10,000 year storm.

It’s always fun to study ice and mud cores — that’s what climatologists would do if you left them alone until retirement time. However, at this point they’re getting paid primarily because we want accurate climate forecasts. If we don’t have climatologists able to even slightly predict a 95th percentile worst case event, it’s time that we found some other climatologists that can do the job.

I think that the real story behind prediction avoidance is a quite real threat of attack from hostile oil barons. The Koch brothers in particular are more than willing to threaten colleges if one climatology professor doesn’t clam up. If you’re a climatologist without tenure you know that you have a bulls eye painted on your back. If you do have tenure, you know that your graduate students could have bulls eyes on their backs and that your departmental budget is related to your cooperation. The fossil fuel industry is one of the leading employers of soft rock geology graduate students, exactly the field that also encompasses climatology.

Scientists have been smeared. It’s reasonable for the to be reticent–on that level. The intimidation is real. Who wants to become embroiled in another Climategate? If you are off by a small bit, then the hired guns and smearmongers come after you, and it is at the very least an anxiety-provoking nuisance.

But I’ve still wondered why scienists haven’t taken us by the lapels and shaken us, 1950’s sci-fi style. It’s because their only lever of persuasion is their credibility, and if it’s tainted with emotion or an accusation of alarmism, that credibility is weakened.

Yes, the scientists are up against diabolically wicked, unscrupulous and outright dangerous creatures, but it is still disappointing to see how few have got ‘the bottle’ to stand up to the thugs, considering the unprecedented importance of doing so.

Following on from last year’s record, this year begins with 1,058km³ less sea ice than this time last year – that’s a trillion tonnes – a third of the amount of sea ice at the record minimum last year.

“The culture of science has in most respects served humanity very well.”

One could write a book on that statement. How the power of science is used depends on the political-economic culture, especially in the “modern” nation-state. Welcome to the Atomic Age, when “fuels” are “too cheap to meter,” yet are threatening every ecological system on Earth. Would that be in the service of science or in the service of an agenda, such as status (or the perception thereof)?

‘…will sink into the abyss of a new Dark Age, made more sinister, and perhaps more protracted, by the lights of perverted science’. Churchill had a florid turn of phrase, but is that not a good description of our current predicament? Science perverted by money power, turned on its head, deracinated by religious fanatics or emasculated by intimidation and smear.

Great post Joe. I’ve been noticing how careful many scientists are in their public pronouncements. The point about the resistance to outlier science seems especially pertinent given a recent study about forest condensation and rain that took two years to publish because it upended some set wisdom about atmosphere physics.

Ditto thanks for this post. As to the ‘outlier science’ I am interested in knowing more about Guy McPherson who gave a speech at the Bluegrass Bioneers Conf. 11-1-12 that was appropriately stark that I saw online. I forwarded this to local climate activists and the reaction was generally very negative. Any insight and reactions are most appreciated.

His main point is that positive feedbacks cannot be reversed, and will spell ‘game over’ in the relatively near future. A recent post summarizes these as follows:

“Positive feedbacks

Methane hydrates are bubbling out the Arctic Ocean (Science, March 2010)

Warm Atlantic water is defrosting the Arctic as it shoots through the Fram Strait (Science, January 2011)

Siberian methane vents have increased in size from less than a meter across in the summer of 2010 to about a kilometer across in 2011 (Tellus, February 2011)

Drought in the Amazon triggered the release of more carbon than the United States in 2010 (Science, February 2011)

Peat in the world’s boreal forests is decomposing at an astonishing rate (Nature Communications, November 2011)

Methane is being released from the Antarctic, too (Nature, August 2012)

Russian forest and bog fires are growing (NASA, August 2012)

Cracking of glaciers accelerates in the presence of increased carbon dioxide (Journal of Physics D: Applied Physics, October 2012)

Arctic drilling was fast-tracked by the Obama administration during the summer of 2012

As nearly as I can distinguish, only the latter feedback process is reversible. Once you pull the tab on the can of beer, there’s no keeping the carbon dioxide from bubbling up and out. Because we’ve entered the era of expensive oil, I can’t imagine we’ll voluntarily terminate the process of drilling for oil and gas in the Arctic (or anywhere else).”

The only real question is the timing, and it will be determined by the amount of reserves driving each feedback, the rates of release, and the accelerating effects of coupling. Without climate models that include these effects, it’s hard to agree or disagree. It’s also not clear to me that some, if not most, of these effects can’t be stopped. With some ingenuity, radical termination of fossil fuel use, and rapid carbon recovery, the process could be slowed substantially. Unfortunately, none of these actions is on the horizon at this point in time.

I think your posts are very compelling and well thought out. I differ on one point: the rate at which we can reduce oil exploration in favor of deploying renewable energy systems. We have within our current toolbox all of the technology we need to achieve a substantially carbon-free energy system. However, it is being blocked from deployment, partly due to a lack of appreciation for what is possible, and because those who will lose are nervous and uncertain how to handle powerful competition.

The environmental community has not focused on truly and rapidly deploying current renewable energy technology, favoring instead a slow-walk approach filled with studies and caution. That approach is a failed relic of past environmental policies which viewed stopping projects as a net good. Now we need a full 180 reversal of that mindset, something which is not built into the current crop of environmental organizations.

As stuck in the mud as current energy companies appear to be, environmental community is equally unsophisticated with what must be done and expressing avid support for it – and getting out of the way to allow it to happen in a timely fashion.

DC, may I respectfully suggest that you have a somewhat blinkered perspective on this.

Perhaps a thought experiment may help here: What if tomorrow, you were able to wave your magic alt-energy wand and make all energy production carbon free?

This would be a great thing as far as global warming goes.

But what would be the consequences to the living planet of the use that all that energy is almost inevitably put to?

You do know that we were already well into the Sixth Great Mass Extinction Event long before the effects of GW really started kicking in, don’t you?

Many of us here are very worried about GW, but primarily because of its consequences for the future of life on the planet. “Solving” GW while further endangering the basic living community is no ‘solution’ from this perspective.

Can you appreciate that point of view, even if you don’t completely share it, perhaps, at this point?

Your one-note-samba that you keep playing over and over and over here ad nauseum–that those nasty environmentalists have been so impudent as to question some of your pet alt-energy projects, and so should be spanked vigorously and without remorse or cessation–is getting a bit…tiresome, and has always been myopic, at best.

Think a bit more broadly, and perhaps your obviously keen mind may contribute more richly to our general understanding of our current predicament (as I see you do here in your enlightening evaluation of Prof. McPherson.)

Environmentalists are not the enemy (and climate scientists are certainly not either, even if some of us would appreciate it if a few more spoke out more clearly and bluntly about what they really know.)

I had a exceptionally nice and interesting conversation with Professor Emeritus McPherson a few days ago. I believe that he has a very cogent and informed perspective. However, even given his dire predictions and their potential validity, the question remains how should we respond. He anticipates collapse and chaos, a perspective which has significant support.

However, despite his concerns, he made clear that he is not going down without fighting against global warming and its effects.

Where we differ slightly, and this a key element, is how we respond to global warming. I believe that we must widely deploy and use the remarkable technology (large-scale wind, solar, etc) which is available to the maximum extent possible and as fast as possible. McPherson holds out less hope for a technological solution, but has not followed modern development to the same extent as I.

An engineer by training, I appreciate how people see things differently. I see a current world of our making which needs improvements and changes to sustain it, to divert it away from an energy cul-de-sac. A biologist might be inclined to not impose more changes on the remaining natural world, even if that stands the best chance of saving it overall.

By the way, Professor McPherson’s website is very well written and fascinating.

Scary to see that McPherson has so many acolytes out there. I have been to his site, and I’ve met some of his fanboys; they’re mostly nutters, and so is he.

I’ll just get to the point: if climate deniers like Tony Watts and Steven Goddard ever had a perfect potential strawman caricature of us people who accept the reality of AGW, he’d be it. And that is precisely one of the reasons why I’ve been very critical of guys like him; he does NOTHING to help our cause. NOTHING!

Prof. Kevin Anderson, former director of the Tyndal climate research centre, is incredibly scathing of some climate modellers (mostly those building IAM’s), going as far as describing them as Machiavellian for putting overly optimistic assumptions in their models so as to arrive at conclusions which give politically acceptable outcomes.

There seems to be a pervading attitude amongst government advisors that we can’t admit that we’re off course for a 2C world by a long way and heading for catastrophe.

For example Anderson quotes a senior political scientist who advices the U.K. government as saying “too much has been invested in two degrees C for us to say it is not possible it would undermine all that has been achieved it would give a sense of hopelessness that we may as well just give in”

He also quotes Ed Miliband, then secretary for the Department of Energy and Climate Change, now leader of the opposition, who on the eve of the Copenhagen meeting in 2009, after having the current path explained to him remarked, “our position is challenging enough. I can’t go with the message that two degrees C is impossible, it’s what we’ve all worked towards”

Scientists need to come out of their damn ivory towers and stand shoulder to shoulder with us poor civilians who are trying to spread the word that runaway Climate Change is the most colossal threat facing mankind (and all life on this planet since the extinction of the dinosaurs!) Communicate in digestible, educated sound bites that travel further. Tell the Truth. We need your help.

I think the very mode of scientific investigation prohibits anything that can be dismissed as conflation. They don’t like to make sweeping statements and rightfully so. But we cannot now overemphasize the nature and scope of the threat.

What you ask for is already happening.
Bear in mind the preeminent climate scientists who have stepped up. Consider Michael Mann and James Hansen, as well as the much longer lists of scientist signers on public letters.

The US EPA has been producing science-based fact sheets on climate change for years now, and the EPA makes an effort to develop age-appropriate materials so people can start at any level of information.

Thanks Joan. Scientists have been warning consistently for 30-40 years and have been consistently ignored by policy makers and public alike. Now, with the same impeccable sense of logic that led to them being ignored, it is time to criticize them regardless of their very public warnings and demonstrations, ME

In 1988 one of my thesis advisors, Myron Mitchell, told me about James Hansen’s message to Congress that year, and we discussed how things might turn out. Mitchell said there were subtle changes in the melting of permafrost that were ominous to the Soviet scientists he’d been talking with, but that politicians anywhere on the planet didn’t seem to take that seriously. Mitchell predicted that by the time things were far enough along to get a political reaction, we would have lost a great deal.
[I’m trained as an environmental scientist, not a climate scientist per se, so I just pitch in where I can.]

Yes, but we need to stop going on and on about hypothetical “runaway” scenarios(which have never happened on Earth, by the way, because that isn’t possible on our planet), and other “doomsday” craziness.

I hate to say it, but the truth is, this is one of the major reasons why we haven’t made as much progress as we could have; not only have the deniers been using this stuff to (falsely) paint us ALL as wackos, but it’s also caused people to stick their heads in the sand, too(I was one of the latter, btw).

We have enough real concerns about climate change as it is; hyperbole hasn’t, won’t, and will NEVER help us fight the problem.

Sorry to jump in so late. The systemic complexity of climate change has plagued science from the start. This limits how much any one model, or collection of models, can forecast.

In advanced non-parametric and multivariate statistics there are some very humbling categories of variability, such as event probabilities that have a low correlation to the variable being measured, or variability that is completely uncorrelated to the tested variables.

The global system is so enormous that it is a credit to the IPCC models that the standard error bands of even a few of them overlap the emergent reality.

In hindsight, the variables may be obvious, but initially they can fall in what Rumsfeld called known-unknowns and unknown-unknowns.

Examples of hindsight to chew on could include the increased burning of coal, particularly high-sulfur coal, or the proliferation of HFC-releasing air conditioners.

So, duh, these are not the kind of phenomena that shouted out their future roles in climate change when placing temperature monitoring stations or putting up weather satellites decades ago.

First, I’m surprised there’s not more consideration given here to how the IPCC “process” itself will almost inevitably tend or bias toward a less extreme “consensus.” This is not malevolent, but predictable.

Second, one upside of that, is that since things are truly worse in the physical world that the IPCC median, and getting worse faster than all but the most extreme IPCC scenarios–then at least the media present newer studies with some sense of alarm–saying, “things are even worse than the IPCC previously predicted.”

Look, you wouldn’t have a clue about the severity of this issue if climate scientists hadn’t been speaking up. They’ve been serving their time in hell all along, trying to get heard.

There’s something very strange about you wanting them to be out in front as a “phalanx” as if they were cannon fodder.

What the February 17 rally can accomplish is show politicians the sheer number of people who care. It doesn’t matter if the scientists are there. In fact I would prefer the scientists were doing what they do best, making measurements – often in difficult terrain – or crunching the data.

Peoplwe care. The question is why are those people not out supporting those building the transformational technology of large-scale wind and solar that will displace hydrocarbon combustion if deployed in sufficiently large amounts?

The focus of the environmental community is like a terrible-2 whose response is “NO” to everything. Try saying yes to the people who are trying to do the right thing.

How about a 350.org rally to support a struggling wind farm project being blocked by “environmentalists?”

How about an explanation for your constant attempts to sow dissension between ‘environmentalists’ and renewable energy promoters? For a start, I have asked you numerous times to explain exactly why you absolutely insist that renewable energy projects MUST be built on the few remaining relics of intact and ecologically precious biospheres, when derelict, degraded and thoroughly wrecked land exists in great abundance, yet you have never deigned to answer. It’s enough to make one suspect your motives.

Of course, scientists being overly cautious in their predictions so as to avoid “drama” and not “alarm” the public with the implications of their research findings run the risk of severe backlash when people come to understand the magnitude of the threat they face. In that event, the public will rightly question why scientists did not disclose the truth of what was in store from a climate getting increasingly hotter. To be overly cautious does not allow for realistic planning for the future. It only allows us to continue to procrastinate awhile longer.

Models are no substitute for informed thinking. Not all effects can be “modeled” with sufficient accuracy to be combined with those things which are well characterized. This does not mean the effects are not present, merely that they are or should be expressed in a more qualitative section.

This is a fascinating window into what is essentially a human behavioral trait, which when confronted with uncertainty and a set of non-linear or step-wise functions, withdraws into standard “continuous function” analysis as taught in nearly all educational frameworks. The concept of the Dirac delta or the plain thinking of who gravity will work on materials such as ice have little to offer when the rest of the equation is relatively simple and continuous.

Just as we have no “model” for asteroid strikes as a function of time, even as we know it might happen, we have no good way to say “bad things will happen” because of x effect. It seems that common sense has or should have a place at the table.

One other point which is not raised is that the underlying estimates of “sensitivity” are not correct, and that many of the underestimated rates of change are linked to increased amounts of accumulated energy in the environment, ocean, ice and atmosphere of the planet.

Those underestimation suggest that considerably more energy is being accumulated than is otherwise accounted for. That is a very bad thing, as it underestimates a feature which cannot be altered but for a reduction in the current atmospheric concentrations of greenhouse gases, something which is astonishingly difficult. But for rigorous prevention, things will accelerate, as the feedbacks are typically non-linear to various degrees.